1. Field of the Invention
The present invention relates to a device for providing marks on a recipient cornea bed of a corneal transplant patient, for facilitating positioning of a donor cornea on the recipient cornea bed for keratoplasty.
2. Discussion of the Related Art
According to a known keratoplasty method, a suitable size of a section of the cornea of a corneal transplant patient (referred to hereinafter as a host patient) is cut out or removed, while a donor cornea is trephined or punched out by a suitable cornea punching device, so that the size of the donor cornea conforms to that of the cutout section of the host cornea. The thus obtained donor cornea is located on the cutout section of the host cornea and then sutured therein. Upon suturing, however, the cornea tends to be inadvertently distorted or displaced due to subtle differences in the manner of suturing from portion to portion, resulting in the incidence of post-transplant astigmatism due to such distortion of the cornea.
In view of the above situation, the inventor of the present invention proposed a cornea punching device as disclosed in co-pending U.S. patent application Ser. No. 07/682,695 now abandoned, for cutting or punching out a donor cornea into a desired shape, in preparation for keratoplasty. The punching device disclosed therein is adapted to cut out or trephine a circular corneal section such that the corneal section (hereinafter referred to as "donor cornea") is provided with a plurality of suction traces which correspond to suction holes or slits formed through a base for supporting the donor cornea when the donor cornea is punched out. More specifically, these suction traces are left on at least a peripheral portion of the surface of the donor cornea such that the traces are equally spaced apart from each other in the circumferential direction of the donor cornea. The thus formed suction traces can be used as a guide for positioning the donor cornea on a recipient cornea bed of a host patient, making it easy for an oculist to suture the graft with the cornea bed. It is thus possible to substantially avoid distortions of the cornea upon suturing, by advertently preventing inclination or displacement of the suction traces on the corneal graft.
Even if the donor cornea is provided by the above-described punching device with the suction traces for the positioning purpose, however, the positioning accuracy is still unsatisfactory in the absence of marks on the side of the host cornea or recipient cornea bed, which marks accurately correspond to the suction traces on the donor cornea. Consequently, there still remains a possibility of post-transplant astigmatism due to subtle distortion of the cornea grafted on the host patient.